Yes, testing is a good option, but other scenarios can leave you stranded, like shorter cells, that can occur very rapidly without warning.

I like the digital testers that provide an impedance value, but the test of how far the conduction voltage drops is a good one... even if it’s just using a multimeter while someone cranks, or a cigarette lighter usb charger with a voltmeter built in...

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

Do tell...?

I frequently multimeter my battery in the mornings, but that's about all I can achieve at home.

I'll get the battery load tested every few months. Never certain whether I'm wasting my time.

__________________
1981 240D 4sp manual. Ivory White.

The first thing is : you're supposed to fully charge it, not just slap a load on it whenever .

In general the inexpen$ive voltage gauges that plug into the cigarette lighter socket are plenty these days, as mentioned if the battery voltage drops below 10VDC when you're cranking the engine that battery is going to fail sooner than later .

When using a load tester it's important to never load below the battery's rated CCA .

Same with alternator testing : my son once got 50 amperes out of a 35 ampere
alternator when he revved it up and loaded it down to 9VDC....

I was on a two day road rally this weekend and one guy had a "Antigravity" brand lithium ion battery that was tiny ~ smaller than a Harley-Davidson Motocycle battery, it had a 350CCA rating and spun his engine like an electric motor .

I may have to look into these for my old Motocycles .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better